Sustainable development is a crucial concept. It’s crucial for the world. But what does it mean? Our starting point has to be, how crowded our world is today. We’re 7.2 billion people. The numbers have soared. We’re up ten times since the start of the industrial revolution. Billions more people are likely to be added to the world’s population in the 21st century. This is making for a very complicated world. A world divided between great wealth and still crippling poverty. A world facing unprecedented environmental challenges. Sustainable development is really two ideas. One, is a way to understand this complicated world. How do the economic, the social, the environmental, the political, the cultural factors fit together? And the second aspect of sustainable development is the idea of sensible goals for this crowded, interconnected planet. How do we make the world both prosperous, fair and also environmentally sustainable, so that our numbers, and our economy don’t overrun the physical planet itself? That’s really the aim of the study of sustainable development. To understand the world and of course, to help improve the world. And we need to get into that complexity. Any idea there’s one answer, one simple, magic formula, one explanation, one force at work; we have to put that aside. We have to embrace complexity, because we are talking about a complicated, interconnected set of relations of a world economy that now spans all parts of the world. And connects all people, all businesses, technologies in flows of trade, finance, ideas, advertising, production systems, but also connects us with the physical Earth, in unprecedented ways. Humanity actually changing the climate, changing what specie survive on the planet, changing the chemistry of the ocean, changing the safety of the air, changing the access and availability of fresh water. It’s an unprecedented situation. It’s a fascinating situation. It will be the challenge of your generation. Let’s see what we can figure out of all of this and how through that knowledge we can do something about it. Have a look at this remarkable, the piece of technology the Maglev in Shanghai. Which carries people at speeds of more than 200 miles per hour, more than 400 kilometers per hour, to and from the city and the airport. It, it’s a magnificent piece of technology. A product of joint work of a major leading engineering companies and Europe and those in China. It’s been operating for the past decade. It is a kind of model of what sustainability can mean in the future. Because if a electric, trains, these, magnetic levitation trains or fast intercity rail based on electricity are powered by, clean electricity. Then we have a way of helping people to move helping goods and services to move in a way that’s safe for environment and technology is exemplified by the Maglev is definitely one way forward. But we also have to realize that not all the world right now is in, in the state of traveling to and from the airport in magnetic levitation. Let’s look a, another remarkable city another great city in many ways, but crowded beyond belief, the city of Dhaka. You see a crowds bustle, and actually a kind of transport you can hardly find anywhere else in the world. I’ve experienced it, it’s astounding to ride in a bicycle, a rickshaw or one of these buses on this incredibly crowded path. Thousands and thousands of people walking to and from work. Life out on the streets. What are we really seeing here? First, we are seeing one of the most crowded places in the world. We are seeing an example of the incredible rise of global population. Bangladesh is a country now, with around 160 million people. That’s more than four times the 37 million people in Bangladesh in the middle of the last century in 1950. Dhaka, itself, is one of the largest cities in the world right now but think of what’s happened. In 1965 Dhaka had about a half a million people. Today Dhaka has more than 15 million people. You can imagine how the infrastructure’s been completely over run. How transport systems, water systems, sanitation systems and all the rest Are facing unbelievable stress with this kind of population increase. This is also part of the reality of our planet. How do you achieve sustainable development in a, very low income, very crowded place like Bangladesh. Especially taking into account how vulnerable low-lying Bangladesh is to the climate change ahead.So, sustainable development for us, first, is a way to understand these complicated challenges. I think it’s useful to think of there being four dimensions to that puzzle. There’s the economics, there’s the societal dimension, how our communities work, culture, civil society, there’s the natural environment and there’s our political or government systems. How do economic, social, environmental and government systems interact? The second way to think about sustainable development is not only as an analytical approach, one that takes a holistic view of society. But also as what we would call a normative or ethical approach, identifying goals for society. Sustainable development urges us to have a holistic vision of what a good society should be. Sometimes people say well good society is a rich society. But we know that can’t quite be it just to focus on the economics. If a country is rich on average, but all the wealth is held by very few people and most of the people are poor, Think most of us would say that’s not a good society in the sense, that we would aspire towards. So social inclusion is the second aspect of a good society. Meaning that economic well being is widely shared among different ethnic religious or racial groups in a country. It’s shared between men and women. So, there’s gender equality, it’s shared among regions of a country, so that there’s not just one pocket of prosperity in a sea of poverty. A third aspect of what we would think to be a good society is one that is a good steward of the natural nvironment. We all know that if we break the physical systems of biodiversity if we destroy the oceans if we deforest the great rain forests, we’re going to lose immeasurably. If we continue on a path that fundamentally changes the Earth’s climate in a way that’s unrecognizable for us in the way that humanity has developed. We’re going to face grave dangers. So from a normative perspective, environmental sustainability certainly seems right. If we care about the well being of our children and future generations. And for most of us we also care very much how government functions. People living in places with massive corruption with lawlessness. Where the politicians are not to be trusted. Where government services are not fair. Where there’s massive discrimination, insider dealing and so forth. This creates a lot of unhappiness. All over the world, people feel happier and better when they can trust their government. But unfortunately, many places in the world, people don’t trust their governments to be honest, to be fair, even to keep them basically secure. So from a normative perspective, we could say that a good society is not only a wealthy society. But is one that is prosperous and inclusive, environmentally sustainable and well governed. And our fundamental question will be how can we take sustainable development as a goal? Use our knowledge of the interconnections of the economy, of society, of the nvironment and of governments. To think through this crowded 21st century in a world of massive divisions of wealth and poverty and world of unprecedented environmental stress. But also in a world of Maglevs and many, many other technological miracles. How can we find our way through, through this century to produce property that is inclusive, that is sustainable. And that is according to decent governance with rule of law, transparency and accountability. There are some very powerful ways forward to meet sustainable development as a goal a shared goal for the planet.